David Luiz will join Paris Saint-Germain this summer, leaving Chelsea after three-and-a-half years in west London.

Confirmation of the Brazilian's transfer to the Ligue 1 champions was broken on Chelsea's official website on Friday.

The exact fee is still unknown, although Sam Wallace's report in The Independent suggests it will be close to £50 million, breaking the world record transfer for a defender.

It's a significant figure—one that doubles the £24 million Chelsea paid for Luiz in January 2011—and outlines Chelsea's intent to comply with UEFA's Financial Fair Play regulations that have recently seen PSG and Manchester City suffer heavy fines.

Luiz's transfer now gives Chelsea significant funds to strengthen their squad over the summer, but how best should Jose Mourinho spend the money?

Patrice Evra has also signed a one-year extension to remain with the Red Devils for 2014-15, adding further doubt as to whether Shaw will be joining the club.

With a potential £50 million windfall from David Luiz's transfer to Paris Saint-Germain, Jose Mourinho now has more than enough financial backing to chase Shaw without worrying too much about Financial Fair Play.

At just 18, the Southampton left-back has a long career ahead of him, and with Ashley Cole's contract expiring in just a few weeks, a move for Shaw will give the Blues a rising star in a position they need to fill.

Sign Yaya Toure

The physical attributes of both players is enough to whet the appetite, and with them pairing together in the Chelsea midfield, it's difficult to imagine many teams combating that combination.

This week has seen Toure's Manchester City future come under question after the club, in his view, failed to properly acknowledge his birthday, per Sky Sports.

With that in mind and with David Luiz's transfer fee behind them, Chelsea should look to capitalize.

City have also been reprimanded by UEFA recently for their failure to comply with Financial Fair Play regulations, so a big bid from Chelsea could very well force their hand as the club looks to make amends.

They may have recently been crowned Premier League champions, but City are vulnerable right now, and Chelsea should look to make the most of that.

Garry Hayes is Bleacher Report's lead Chelsea correspondent. Follow him on Twitter @garryhayes